THYROID

Tess Jacob M.D

Endocrinology

Livingston Public Library

Thursday, November 30, 2017

Thyroid gland

• What is the thyroid gland?

• What is its function?

• What hormones does it secrete?

• Common conditions of the thyroid

• Thyroid nodules

• Questions???

• Butterfly shaped endocrine gland

• In front lower neck

• Below Adam’s apple

• 2 lobes

• Wrap either side of windpipe

• Manages growth and energy metabolism

• Role of thyroid ->produce thyroid hormones

• Essential for life

• Secreted into the blood and then carried to every tissue in the body

• Thyroid hormones: T4, T3

• Thyroid hormone helps the body use energy, stay warm and keep the brain, heart, muscles and other organs working as they should

• T4 under influence of TSH by pituitary gland

• T4 inactive/storage form(thyroid)

• Converted to T3 active form when

reaches organs and body tissue

• Numbers –iodine atoms

• Iodine(element for thyroid hormone)

• Iodine not made by the body so we rely on our diet

• Too much and too little iodine is bad for you

• Too little iodine – Goiter and hypothyroidism

Common sources of dietary iodine

• Cheese

• Cows milk

• Eggs

• Frozen yogurt

• Ice cream

• Iodine containing multivitamins

• Iodized table salt

• Saltwater fish

• Seaweed( kelp)

• Shellfish

• Soy milk

• Soy sauce

• Yoghurt

Thyroid gland

Symptoms of hypo(underactive) and hyperthyroidism

(overactive)

• Show of hands ??

• Nonspecific

Hypothyroidism

• Hashimotos thyroiditis

• Surgery

• Radiation treatment

• Thyroiditis

• Medications

• Too much or too little iodine

• Damage to pituitary

How to diagnose

• Bloodwork

• High TSH and low FT4

• Consider antibodies to check if Hashimotos thyroiditis

Subclinical Hypothyroidism

• When to treat?

• How to treat hypothyroidism?

• Levothyroxine vs Synthroid vs Tirosint

• Levothyroxine and liothyronine or cytomel

• Side effects of medication -> overtreatment vs undertreatment

Pregnancy goals

• When to treat?

• What to do if you find out you are pregnant and have underactive thyroid?

Hyperthyroidism

• Graves disease

• Toxic nodular/toxic multinodular goiter

• Thyroiditis

• Medication

How to diagnose

• Blood tests

• Low TSH and high TT3, FT4

• Thyroid uptake scan

How to treat?

• No single treatment is best for all hyperthyroid patients

• Treatment usually individualized (age, needs)

• Antithyroid drugs and Beta blockers vs Radioactive Iodine vs Surgery

Antithyroid drugs

• Methimazole/Tapazole

• Propylthiouracil or PTU

• 20-30% of those with Graves dx can go into remission with ATD’s for 12-18mo’s

• Toxic MNG – can use as bridge to RAI or surgery

Side effects

• Allergic reactions – 5%, Hives, red rash

• Rarer and serious –suppression of white blood cells. Notify your physician immediately if you get fever and sore throat

• Liver toxicity – dark urine, nausea, fatigue, abdominal pain

Radioactive Iodine

• More than 70% of adults in the US with hyperthyroidism are treated with RAI.

• Pill form

• Ingestion of RAI - uptake of iodine by the overactive thyroid tissue from the bloodstream.

• Whatever not taken up, leaves your body over days

• Over weeks to months, RAI destroys tissue that took it up.

• When used to treat Graves disease, you often become hypothyroid following that but that is easily treated with levothyroxine.

Surgery

• Individualized

• Hyperthyroidism should first be controlled prior to surgery with antithyroid drugs

• Permanent cure

• Need levothyroxine replacement

• Complications: low calcium, vocal cord nerves - hoarseness

Goiter

Goiter

• Abnormal enlargement of thyroid

• Can have normal thyroid function

• Can have overactive or underactive thyroid

• If very large, can cause obstructive symptoms

Causes of Goiter

• Iodine deficiency

• Hashimoto’s thyroiditis

• Graves disease

• Nodules

Thyroid nodules

• Very common

• Diagnosed on physical exam or more commonly incidentally on imaging done for other reasons

• Thyroid Ultrasound to evaluate it

• Abnormal growth of thyroid cells forming a lump within the thyroid gland

• Majority are benign

Thyroid ultrasound

Fine needle aspiration biopsy

• Do not need to fast on the day of the biopsy

• Safe and simple procedure

• Usually do not need to hold blood thinners

• Gel with ultrasound to take images and ensure correct placement of needle when sampling

• Small needle – smaller than a blood draw used to sample cells from nodule

Cases

• 30yo F – fatigue, low mood, constipation and depression, BMI 26

• 59yo M – fatigue, leg swelling, sleepy during the day, BMI 35

• 20yo F – fatigue, lack of concentration, hair loss, sleeping too much

• 50yo M – palpitations, lack of energy, anxiety, work stress

• 22yo F – palpitations, losing weight, eyes bulging, tremors, anxiety

Thank you!